Marine food web perspective to fisheries-induced evolution

Abstract

Fisheries exploitation can cause genetic changes in heritable traits of targeted stocks. The direction of selective pressure forced by harvest acts typically in reverse to natural selection and selects for explicit life-histories, usually for younger and smaller spawners with deprived spawning potential. While the consequences that such selection might have on the populational dynamics of a single species are well emphasised, we are just beginning to perceive the variety and severity of its propagating effects within the entire marine food webs and ecosystems. Here, we highlight the potential pathways in which fishing-induced evolution, driven by size-selective fishing, might resonate through globally connected systems. We look at: i) how a size-truncation may induce shifts in ecological niches of harvested species, ii) how a changed maturation schedule might affect the spawning potential and biomass flow, iii) how changes in life-histories can initiate trophic cascades, iv) how the role of apex predators may be shifting, and v) whether fishing-induced evolution could co-drive species to depletion and biodiversity loss. Globally increasing effective fishing effort and the uncertain reversibility of eco-evolutionary change induced by fishing necessitate further research, discussion, and precautionary action considering the impacts of fishing-induced evolution within marine food webs.